This northern summer will be the tipping point, the moment the high-pitched anxiety about the disintegration of Europe starts to colour all political calculation. The fast tempo of the street attacks in Germany and the cumulative terror assaults in France all point in one direction: imperfectly integrated migrant communities and damaged rootless refugees are beginning to turn on their host countries.

As a result, President Francois Hollande’s countrymen no longer trust him, while the Germans question the competence and judgment of Chancellor Angela Merkel. The confidence in the integrative idea of Europe is evaporating.

That is about to take a turn for the worse. Recep Tayyip Erdogan’s post-coup coup in Turkey — the President’s mass round-up of critics — makes plain that the flawed grand bargain with the EU on stemming the refugee exodus cannot hold for much longer. For the past few months it has cut the numbers of boatpeople and allowed Merkel to believe she is still clinging on to public support for a liberal refugee policy. Even before Erdogan’s latest authoritarian lurch, however, the deal was beginning to look wobbly.

The original idea was that Turkey should essentially become a holding pen for refugees in return for EU cash and the right for Turkish citizens to travel freely in Europe. Migrants rejected by Greece would be taken back by the Turks, people-smugglers thwarted. For every illegal migrant taken back by Ankara, the EU agreed to take a properly documented refugee from the Turkish camps. What is already happening, though, is that returned migrants are being dumped in detention centres; according to Amnesty International, some have even been sent back to Syria.

Migrants rejected by the EU are supposed to be returned to a “safe” country. Yet even before the tanks appeared on Turkish streets, the country did not look very safe to people on the move. EU states turned a blind eye. Now Erdogan is making it all but impossible to work with him. He wants to introduce the death penalty; he has imposed a state of emergency. Greece is rightly thinking twice about sending people back across the Aegean.

The EU had demanded changes in Turkey’s anti-terror legislation before granting visa liberalisation. Instead, Erdogan is becoming tougher and he has little interest in accelerating entry into the EU. We have lost all influence over him; he has eaten the carrots and broken the sticks.

It is not only the Germans who have been noticing that the refugees offered up by the Turks for resettlement in the EU include an unusually high number of young men with mental health problems. The sheer volume of Germany’s migrant intake — 1.2 million last year — means that many of the vulnerable are slipping through the net. The machete and bomb attacks that have hit German streets are thus being seen partly as an indictment of Merkel’s open-door policy. Germans scoff when they hear from the Interior Minister that 59 asylum-seekers from the Middle East are under investigation for terrorist connections. What does he know, they ask, what does anyone in government know about the background of this huge alien presence?

The calendar of European decline begins not with last month’s referendum in Britain or the unrest in Turkey. For the Germans, at least, it probably started on New Year’s Eve in Cologne, when hundreds of women were sexually assaulted by migrant workers and asylum-seekers. Information was initially withheld by the authorities because they did not want to admit the state could no longer cope. The tensions could be concealed as long as they were restricted to the Muslim bullying of Christians in overcrowded gym halls that doubled as refugee dormitories. Now, the problems are tumbling into the streets, into public space.

Brexit, of course, has become a symbol of the fragmentation that could strike the whole continent; a leading European power seemingly no longer behind European solutions to European problems. That made the French and the Germans angry with Britain for leaving. Soon, though, that anger will turn on their own leaders. Eight out of 10 French people, according to a new survey, would accept limitation on their civil liberties to combat terrorism at home. That’s music to the ears of the Far Right. Their guiding maxim has always been that the price of a diversified society is diminished individual freedom. Mainstream parties, by not checking the inflow of foreigners, or by looking away from crimes committed by them, were thus betraying core democratic values as well as abandoning their duty to keep citizens secure. There are plenty of reasons to believe that the Far Right would make an even bigger hash of things. But on European streets they are winning the argument.

The speed of these developments may seem dizzying at the moment but all the signs point to further acceleration. If the refugee exodus via Turkey picks up again, all bets are off. Even if Erdogan merely threatens to open the sluices unless he is given concessions from the EU on visa liberalisation, the political mood will become toxic.

In September the far-right candidate for the Austrian presidency, Norbert Hofer, will probably win a re-run of the ballot he narrowly lost this year.

A risky constitutional referendum in Italy in October may end up weakening the government, and the eurozone. There will be a referendum in Hungary that will probably reject EU migration quotas. By the northern spring of next year, the ultranationalist Geert Wilders will be capturing large chunks of voters in the Dutch elections. And Marine Le Pen seems set to progress at least into the final round for the French presidency. Both Le Pen and Wilders have taken heart from Brexit and are promising their own referendums. By the time the Germans get to vote in the northern autumn of next year, the continent will already have changed. A new summer migrant surge will leave Merkel’s Christian Democrats struggling to defeat the Far Right.

There was a time when crises were supposed to make Europe stronger. Today they are just making the European elite punch-drunk (perhaps that is Jean-Claude Juncker’s problem). The EU has overextended itself, it is weakly led, its borders are troubled. After the British referendum, the metropolitan consensus was that the result was a crazed howl of anger at the establishment. Policies are being adjusted accordingly. Today, though, that vote appears to have been eminently rational, a vote to be in some way quarantined from the turmoil brewing across the Channel.